Last updated: June 24, 2025
In New Castle, United States, the average temperature in December hovers around 2°C (35°F). However, be prepared for temperature swings, as it can plummet to a chilling -23°C (-10°F) or rise to a comfortable 17°C (64°F). Expect about 81 mm (3.2 in) of precipitation spread over 11 days, contributing to an average humidity of a high 87%, making the air feel quite damp.
In December in New Castle, the average temperature is 2°C (35°F). The maximum can reach 17°C (64°F), while the minimum can drop to as low as -23°C (-10°F). It's advisable to pack layers and be prepared for a wide range of temperatures if you plan to travel during this time.
In New Castle in December, the precipitation amount is 81 mm (3.2 in) over a span of 11 days.
In New Castle in December, humidity is 87%. With an average temperature of 2°C (35°F), this humidity feels like a damp chill that seeps into your bones, making traveling feel uncomfortable and heavy, as each breath carries a hint of the cold, moist air that lingers around you.
In New Castle in December, the maximum UV index is 3, which corresponds to a moderate Exposure Category. The time to burn is approximately 30 minutes. For more details on the hourly UV index in New Castle, you can check the information here.
UV Risk Categories
Weather in New Castle varies notably across the year, with each month offering distinct climate conditions. This page compares December’s weather to other months in New Castle, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | -1°C (30°F) | 78 mm (3.1 inches) | 87% | moderate |
| February Weather | 0°C (33°F) | 99 mm (3.9 inches) | 85% | moderate |
| March Weather | 5°C (42°F) | 120 mm (4.7 inches) | 86% | high |
| April Weather | 11°C (51°F) | 99 mm (3.9 inches) | 84% | very high |
| May Weather | 17°C (64°F) | 140 mm (5.5 inches) | 79% | very high |
| June Weather | 22°C (72°F) | 120 mm (4.7 inches) | 82% | extreme |
| July Weather | 24°C (76°F) | 112 mm (4.4 inches) | 79% | very high |
| August Weather | 23°C (73°F) | 93 mm (3.7 inches) | 70% | very high |
| September Weather | 20°C (69°F) | 89 mm (3.5 inches) | 69% | very high |
| October Weather | 14°C (57°F) | 101 mm (4.0 inches) | 76% | high |
| November Weather | 5°C (41°F) | 93 mm (3.7 inches) | 88% | moderate |
| December Weather | 2°C (35°F) | 81 mm (3.2 inches) | 87% | moderate |